No – the Colorado Supreme Court recently held that because medical marijuana remains illegal under federal law, an employee’s off-duty use of prescribed medical marijuana was not protected by the state’s lawful activity statute.
In Coats v. Dish Network, the employer fired an employee who tested positive for marijuana after using medical marijuana during non-work hours.  The medical marijuana used by the employee was lawfully prescribed under Colorado law, which also recently legalized the recreational use of marijuana.  2015 CO 44 (Colo. June 15, 2015).  The employee sued and alleged that the termination violated the Colorado lawful activity statute.  Unless limited exceptions apply, the Colorado lawful activity statute prohibits employers from terminating “the employment of any employee due to that employee’s engaging in any lawful activity off the premises of the employer during nonworking hours.”  See Colo. Rev. Stat. 24-34-402.5.
The Colorado Supreme Court held that the lawful activity statute did not protect the employee’s lawful use of medical marijuana because even though it was legal under state law, it remained illegal under federal law.  The court held that the term “lawful” in the statute only applied to “those activities that are lawful under both state and federal law.”  Although not necessarily binding in other states, the Colorado Supreme Court’s decision is persuasive precedent that suggests that off-duty marijuana use may not be protected under many states’ lawful consumable products statutes.
Like Colorado, Minnesota has a lawful consumable product statute, which generally allows employees to use “lawful” products during non-work hours.  See Minn. Stat. §181.938.  Under the reasoning of Coats, this statute likely does not protect off-duty marijuana use.  Therefore, if an employee tests positive for marijuana because the employee used recreational marijuana in a state where recreational marijuana was legal (such as Colorado or Washington), the lawful consumable products act would arguably not protect that employee.
Employers need to be careful, however, because some states explicitly protect the off-duty use of medical marijuana.  For example, under Minnesota’s new medical marijuana law, which will take effect on July 1, 2015, an employer generally cannot discipline an employee for the lawful, off-duty use of medical marijuana.  If this law had been in effect in Colorado, the Coats case likely would have turned out differently.
Takeaway:  The Coats case suggests that off-duty recreational use of marijuana will not be protected by Minnesota’s lawful consumable products statute even if the use occurs in a state where it is legal.  On the other hand, Minnesota law generally prohibits employers from disciplining employees for the lawful use of medical marijuana, so employers will still need to exercise caution when disciplining employees for marijuana use.